Shrinking semiconductor feature sizes has led to an increase in the number of circuits and functions that can be implemented on a single integrated circuit. In the automotive area, single chip solutions are becoming available for radio frequency (RF) sub-systems such as automotive radar, audio and video entertainment systems, automotive control systems, and automotive safety systems. Often, the limiting factor in how many features can be included on a single chip is not the amount of circuitry that can be included on a single piece of silicon, but rather the number of pins that can be included on a package.
In safety critical automotive systems, such as airbag controllers, safety related redundancy and failure modes often dictate increased functionality for a particular subsystem. For example, a particular component may be configured to operate in a “failure mode” or a “safety mode” in addition to its primary function during normal operation. One example of this is an engine or motor controller that performs a predetermined deactivation sequence upon notification of an accident or other failure. The implementation of the predetermined deactivation sequence often requires the presence of additional signaling and power supply paths to support the failure modes and/or safe operation during accidents. The implementation of such additional signaling and power supply paths poses challenges to the design of single-chip systems and subsystems with respect to the number of package pins used by the single-chip system.